Lori Brown shows us a few methods for finding references to tables:
I use sys.sql_modules to check for references to strings in stored procedures. You might think that this would not be necessary since you can find that in sys.dm_sql_referencing_entities for those. However, what if you do a lot of stuff in stored procedures that uses dynamic SQL to create objects or other stored procs on the fly? sys.dm_sql_referencing_entities might miss those. For example, when I look in sys.sql_modules for all occurrences of Sales.Orders I find more.
This is necessarily an incomplete list, but at least it gets you started.